1 files changed, 59 insertions, 0 deletions
diff --git a/src/plot/plotters_backend/t_test.rs b/src/plot/plotters_backend/t_test.rs
new file mode 100755
index 0000000..741cc9e
--- /dev/null
+++ b/src/plot/plotters_backend/t_test.rs
@@ -0,0 +1,59 @@
+use super::*;
+use crate::report::ComparisonData;
+use std::path::Path;
+
+pub(crate) fn t_test(
+    path: &Path,
+    title: &str,
+    comparison: &ComparisonData,
+    size: Option<(u32, u32)>,
+) {
+    let t = comparison.t_value;
+    let (xs, ys) = kde::sweep(&comparison.t_distribution, KDE_POINTS, None);
+
+    let x_range = plotters::data::fitting_range(xs.iter());
+    let mut y_range = plotters::data::fitting_range(ys.iter());
+    y_range.start = 0.0;
+    y_range.end *= 1.1;
+
+    let root_area = SVGBackend::new(&path, size.unwrap_or(SIZE)).into_drawing_area();
+
+    let mut chart = ChartBuilder::on(&root_area)
+        .margin((5).percent())
+        .caption(format!("{}: Welch t test", title), (DEFAULT_FONT, 20))
+        .set_label_area_size(LabelAreaPosition::Left, (5).percent_width().min(60))
+        .set_label_area_size(LabelAreaPosition::Bottom, (5).percent_height().min(40))
+        .build_ranged(x_range, y_range.clone())
+        .unwrap();
+
+    chart
+        .configure_mesh()
+        .disable_mesh()
+        .y_desc("Density")
+        .x_desc("t score")
+        .draw()
+        .unwrap();
+
+    chart
+        .draw_series(AreaSeries::new(
+            xs.iter().zip(ys.iter()).map(|(x, y)| (*x, *y)),
+            0.0,
+            &DARK_BLUE.mix(0.25),
+        ))
+        .unwrap()
+        .label("t distribution")
+        .legend(|(x, y)| {
+            Rectangle::new([(x, y - 5), (x + 20, y + 5)], DARK_BLUE.mix(0.25).filled())
+        });
+
+    chart
+        .draw_series(std::iter::once(PathElement::new(
+            vec![(t, 0.0), (t, y_range.end)],
+            DARK_BLUE.filled().stroke_width(2),
+        )))
+        .unwrap()
+        .label("t statistic")
+        .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], &DARK_BLUE));
+
+    chart.configure_series_labels().draw().unwrap();
+}